1. Technical Field
The present invention relates to a variable wavelength interference filter which selects light of a desired target wavelength from incident light and emits the selected light, an optical module including this variable wavelength interference filter, an optical analysis device including this optical module, and a method for manufacturing the variable wavelength interference filter.
2. Related Art
In the related art, a spectral filter is known which acquires light of a specific wavelength from incident light by reflecting light between a pair of reflection mirrors, transmitting light of a specific wavelength and canceling light of other wavelengths by interference. Also, as one such spectral filter, a variable wavelength interference filter is known which selects and emits light to be emitted by adjusting the distance between the mirrors (see, for example, JP-A-2007-299008).
The variable wavelength interference filter described in JP-A-2007-299008 includes a fixed mirror formed on an SOI (silicon on insulator) substrate, and a movable mirror having a penetration hole and arranged to face the fixed mirror. In this variable wavelength interference filter, air resistance generated by air compression at the time of driving is relaxed (mitigated) via the penetration hole of the movable mirror, thus restraining vibration of the movable mirror.
However, in the variable wavelength interference filter described in JP-A-2007-299008, an internal space which houses a movable portion at atmospheric-pressure and the movable mirror receives air resistance at the time of driving. Therefore, there is a problem in that sufficient responsiveness of the movable mirror cannot be secured because of the air resistance.